In an effort to bolster a mostly unproven bullpen, the Mets tried to sign veteran Grant Balfour, according to an industry source. The 36-year-old Balfour on Thursday agreed to a two-year contract with the Rays worth $12 million.

The dollars offered may have been similar, but the Mets had to get “creative” with their offer, according to the source, indicating there might have been incentives or deferred cash involved.

“Not the same” the source said of the two offers. “[Tampa Bay’s] offer was cleaner.”

Earlier this winter, Balfour reached agreement with the Orioles, only to have the deal fall apart because the team was concerned about the results of his physical.

The Mets have a need for a veteran bullpen presence after choosing not to re-sign LaTroy Hawkins, who received a one-year deal with the Rockies worth $2.25 million.

Bobby Parnell, Vic Black, Jeurys Famila, Josh Edgin and Scott Rice are the main components of the Mets’ bullpen heading into spring training.